docs: def local_time_to_online(dt=None):
      """Converts datetime object to a UTC timestamp for AGOL.
  
      Args:
          dt (datetime): The :py:class:`datetime.datetime` object to convert. Defaults to ``None``, i.e., :py:func:`datetime.datetime.now`.
  
      Returns:
          float: A UTC timestamp as understood by AGOL (time in ms since Unix epoch * 1000)
  
      Examples:
          >>> arcresthelper.common.local_time_to_online() # PST
          1457167261000.0
          >>> dt = datetime.datetime(1993, 3, 5, 12, 35, 15) # PST
          >>> arcresthelper.common.local_time_to_online(dt)
          731392515000.0
      See Also:
         :py:func:`online_time_to_string` for converting a UTC timestamp
  
      """
      is_dst = None
      utc_offset = None
      try:
          if dt is None:
              dt = datetime.datetime.now()
  
          is_dst = time.daylight > 0 and time.localtime().tm_isdst > 0
          utc_offset =  (time.altzone if is_dst else time.timezone)
  
          return (time.mktime(dt.timetuple()) * 1000) + (utc_offset * 1000)
      except:
          line, filename, synerror = trace()
          raise ArcRestHelperError({
                      "function": "local_time_to_online",
                      "line": line,
                      "filename":  filename,
                      "synerror": synerror,
                                      }
                                      )
      finally:
          is_dst = None
          utc_offset = None
  
          del is_dst
          del utc_offset